This application claims the priority of German application 101 59 087.3, filed Dec. 1, 2001, the disclosure of which is expressly incorporated by reference herein.
Reference is also made to co-pending U.S. application Ser. No. 10/307,525, filed on the same date as the present application, titled xe2x80x9cINTERNAL COMBUSTION ENGINExe2x80x9d.
The present invention relates to an internal combustion engine including a crankcase in which a crankshaft is held, an oil guide housing positioned beneath the crankcase, and an oil pump equipped with a drive sprocket for supplying lubricating oil positioned in the oil guide housing, and in which the oil pump supplies lubricating oil to consumers from an oil trap in the oil guide housing.
In forced-feed lubrication of an internal combustion engine, the process of positioning a required oil pressure pump underneath the crankshaft in an oil guide housing and/or in an oil pan (see e.g., Fachkunde Kraftfahrzeugtechnik, page 323 ff., Europaxe2x80x94Lehrmittel Publishers, 26th Edition), is known. The oil pressure pump is preferably driven via a chain drive that is driven by the crankshaft.
The problem with such a system is that the drive chain and/or the drive gear for the oil pressure pump is partially immersed in the oil trap; hence the oil is drawn along by the drive chain. The lubricating oil carried along by the chain results in undesirable foaming of the oil in the crankcase; this problem is perpetuated within the cylinder head housing when the lubricating oil is further carried forward by a timing chain that drives the camshaft in the cylinder head housing.
It is thus one object of the invention to prevent lubricating oil that is drawn along by the drive chain in the oil pump from escaping from the oil trap in the crankcase and/or entering the cylinder head of the internal combustion engine.
This object is attained by having the sprocket encompassed by a cover, and providing elements on the sprocket cover for scraping, separating, or scraping and separating lubricating oil that is drawn along by a chain, driven by the sprocket, out of the oil trap in the direction of the crankcase.
By providing the oil pressure pump with a sprocket cover that is equipped with a base for stripping and/or separating the lubricating oil being drawn along by the chain, the lubricating oil that is drawn along and/or carried over by the drive chain will be returned to the oil trap and/or will not enter the crankcase or the cylinder head housing.
Further advantageous embodiments of and improvements on the internal combustion engine specified are reflected in dependent claims.
The sprocket cover is advantageously provided with openings in the area of the chain guide, wherein the rims of these openings serve as oil-scraping edges for the lubricating oil.
The sprocket cover is pot-shaped in design and equipped with a circumferential side panel, in which the openings provided with the oil-scraping edges are positioned.
In an advantageous manner, the revolving drive chain is fed through a number of the openings that are equipped with the oil-scraping edges.
One embodiment of the invention is specified in greater detail in the following description and in the drawings.